The present invention relates to an arrangement for damping vibrations in a transmission shifting system for vehicles, and more particularly, to an arrangement comprising a shift rod arranged in the vehicle in a rotatable and axially movable manner and adjustable by a manually operable shift lever and, in an axial direction thereof, comprises at least two rod sections connected by a joint permitting rotating and axial movements of the shift rod.
In transmission shifting systems, engine-excited oscillations introduce vibrations via the outside shifting device, thus particularly the shift rod, into the gear shift lever. When the shifting device on the shift lever head is operated, the high-frequency component of these vibrations generates an unpleasant and disturbing shifting sensation. It was found that the vibrations are caused mainly by the vibration components in the longitudinal direction of the shift lever.
DE-A-36 34 174 shows a system for damping such vibrations. The shift rod situated between the gear shift lever and the transmission is divided into two parts by a universal joint. The two rod sections are connected by the joint such that the shift rod can carry out rotational and axial movements. In order to dampen or uncouple the vibrations occurring radially about the longitudinal axis of the shift rod and resulting from the engine transmission unit, spring elements, preferably O-rings, are provided on each rod section. The spring elements are enclosed by a stiff connection member which, in turn, is separated from the shifting rod sections. However, the known arrangement requires relatively high expenditures.
It is, therefore, an object of the present invention to provide a simpler vibration damping arrangement. This object has been achieved in accordance with the present invention by providing that the joint is a hinge with an axis of rotation extending perpendicularly to the axial direction of the shift rod, the at least two rod sections are connected with one another by way of a support bearing having a predetermined play, and a bearing axis of the support bearing extends parallel to the axis of rotation of the hinge.
In contrast to the prior art, the present invention utilizes only a hinge to which a support bearing is assigned. The hinge and the support bearing can be constructed in a simple manner by pins and sleeves which are fastened to the respective rod sections by, for example, welding.
As mentioned above, particularly vibrations which are introduced in a multi-axial manner have a disturbing effect on the shift lever. The divided shift rod of the arrangement according to the present invention is correspondingly capable of preferably damping these vibration components. If, in addition to the support bearing, a certain play is also permitted in the case of the hinge, it is now possible to also dampen to a certain degree the vibration component which occurs perpendicularly thereto. However, in this situation, the shifting will result in a somewhat softer, doughy shifting sensation.
In order to avoid noise problems, it is also an advantageous feature of the present invention to fill the clearance formed by the play at least partially with an elastic layer. In addition, the elasticity of the layer improves the damping of the vibrations.
On the whole, the arrangement according to the present invention provides a precise shifting sensation and largely prevents the disturbing vibration of the shift lever.